1. Field of the Invention
The present invention relates to a binder which can bind many sheets of paper to be bound even if those are increased in number.
2. Prior Art
A typical conventional binder will be explained by referring to FIG. 32. In this binder, supporting portion 1 is connected to a rear plate 3 through a hinge 2 and by bending an end of the rear plate 3 at a right angle a stopper mounting portion 4 is provided. On this stopper mounting portion 4 a stopper 5 is mounted rotatably in direction of an arrow through a hinge against biasing force of a spring 6. When binding papers, after inclining the rear plate 3 in a position indicated in phantom line, into punched holes of the papers paper-binding-cylinders 8 provided on the supporting portion 1 are inserted, then while raising said rear plate 3' to the position of 3, a member 9 is located behind the stopper 5 and those are unified by engaging projections 11 provided on the surface of the member 9 with stopping holes 12 formed on the stopper 5.
A well known clamp device in a binder is formed in such a manner as a pair of end bases of a clamp are supported rotatably on the inside of a flange of a supporting frame having U-letter shape in section, gears are formed on said pair of end bases and a worm gear engaging with said gears is supported on a rib portion of said frame as being pivoted thereon, by rotation of which both tip ends of said pair of clamps come close or get away with each other, thereby an opening extent of said tip ends can be adjusted arbitrarily to settle the clamping force of said tip ends of the clamp.
In those conventional examples as mentioned above, each has issues to be improved as follows. First, in the example illustrated in FIG. 32, the number of sheets of paper to be bound is limited by the height H of the rear plate 3. That causes such problem as necessary papers to be bound as one document in one binder have to be bound separately in another binder because of the thickness of the papers thicker than the size of the height H. Further, since the height H of the rear plate 3 is prepared in advance sufficiently high in order to bind many sheets of paper, even if a small sheets of paper are bound, such binder needs a sufficient space therefor in a shelf, which causes the binder to be improved in the light of accommodation space in a shelf.
Next, a conventional clamp device has the following problems. That is, although it is advantageous to bind comparatively small sheets of paper, because the opening degree of the clamp and a clamping force are acquired appropriately, when a number of sheets is increased to such extent as distal ends of the clamp members are spread wider than the basement space of the clamp members due to the volume of papers, some papers located at intermediate portion between the clamp members are apt to be disassembled therefrom, which is troublesome to re-collect such separated papers in order.
On the other hand, in order to prevent such papers from being disassembled, it is necessary to make the height of a supporting frame sufficient and to use the clamp in such a manner as the basement space of the clamp is kept wider than the space between the distal ends of the clamp members even if many sheets of paper are clamped. For that purpose, like in the afore-mentioned conventional example, even if a number of sheets to be bound is small, a space to be taken by such binder is the one in which the predetermined thickness of the binder can be accommodated, which raises a problem to be solved in the light of binder accommodation space in a shelf.
Next, as a third conventional binder, here is such type of binder as using a pair of boards i.e. a front cover and a rear cover, in which these two boards are drawn by drawing springs. Papers are clamped between these covers under the drawing force of such springs, so that, stronger the force of spring, stronger the force of opening these covers for adding some additional papers against the spring force is needed, which rises a problem to be solved in the light of easiness to use such binder. The present invention is to provide a binder which can regulate the thickness of a binding device in accordance with a volume of papers to be bound i.e. in case a volume is small, the thickness becomes small where accommodation space in a shelf is advantageous, and in case the volume is large, the thickness becomes large in accordance with the volume of papers.